Conventionally, as a configuration for transmitting a driving force, for example, of an engine or a motor to a driven side, a configuration that the pulleys are coupled to shafts of a driving side and the driven side and a friction transmission belt is wrapped over these pulleys has been widely known. In the above described friction transmission belt, a high power transmitting ability is required as well as quietness during running the belt is required. In order to satisfy these requirements, it is required to reduce a friction coefficient of a belt surface as long as a predetermined power transmitting ability can be kept. For example, in a case where the friction transmission belt is a V-ribbed belt, as it is disclosed in Patent Document 1, short fibers which are oriented in a belt width direction are mixed into a compression rubber layer, which contacts the pulleys, for the sake of reinforcing the compression rubber layer, and the short fibers are provided so as to be projected out from the belt surface to reduce the friction coefficient of the belt surface, thereby improving a noise reduction and an abrasion resistance.
The above Patent Document 1 discloses a configuration in which a rubber component is mixed with powders made of a thermosetting resin for the purpose that the friction coefficient can be reduced even in a case where the short fibers of the compression rubber layer drop out or are worn out.    [Patent Document] Japanese Patent Application Laid-open Publication No. 2006-266280